Semiconductor devices (IC chips) used in CPUs of computers in recent years tend to be characterized by increasingly higher speed and higher functions, and the number of terminals tends to increase and the pitch between the terminals tends to become narrower correspondingly. Generally, a multiplicity of terminals are densely arranged in array form on the bottom surface of the IC chip, and such terminal groups are connected to terminal groups on the motherboard side in flip chip form. However, since there is a large difference in the terminal pitch between the terminal groups on the IC chip side and the terminal groups on the motherboard side, it is difficult to directly connect the IC chip onto the motherboard. For this reason, a technique is generally adopted in which the IC chip is mounted on a wiring board for IC chip mounting, and the wiring board for IC chip mounting is mounted on the motherboard. As the wiring board for IC chip mounting of this type, those have hitherto been proposed in which a capacitor is embedded in a core board formed of a polymeric material to form a core portion, and buildup layers are respectively formed on the obverse surface and the reverse surface (e.g., refer to JP-A-2005-39243). In addition, a wiring board for IC chip mounting in which a capacitor is incorporated in an insulating layer of the wiring board has also been hitherto been proposed (e.g., refer to JP-A-2004-228190).
To attain the stabilization of a power source due to the low inductance between the capacitor and the IC chip, it is preferable to make the distance between the capacitor and the IC chip as short as possible. Accordingly, it is conceivable to incorporate the capacitor in a buildup layer which is closer to the IC chip than the core board.